TY  - JOUR
AU  - V. A. Il'in
TI  - Properties of spectra of nonnegative self-adjoint extensions of elliptic operators and exact conditions for the convergence and Riesz summability of Fourier series of various classes of functions
JO  - Matematičeskie zametki
PY  - 1970
SP  - 515
EP  - 523
VL  - 7
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_1970_7_4_a16/
LA  - ru
ID  - MZM_1970_7_4_a16
ER  -